1. Field of the Invention
The present invention relates to a chip package device and a manufacturing method thereof.
2. Description of the Related Art
Generally, semiconductor packaging refers to the use of an encapsulant to enclose a semiconductor chip with provision of electrical connections outside the encapsulant for connecting an external device or circuit. In current semiconductor packaging methods, the ball grid array package (BGA) technology is most commonly used for packaging high density and high pin count chips. In a conventional BGA package, a semiconductor chip is placed on a printed circuit board and wire-bonded to the printed circuit board. An encapsulant is employed to enclose the semiconductor chip and wires. Solder balls are formed on the back of the printed circuit board to electrically connect an external device and the semiconductor chip.
While the circuit of the semiconductor chip is under operation, the semiconductor chip generates heat. In a conventional BGA package, the semiconductor chip is encapsulated by an encapsulant having poor thermal conductivity. Consequently, the heat from the semiconductor chip cannot be easily dissipated.
Some BGA packages have heat sinks in the encapsulant for facilitating the heat dissipation of semiconductor chips. However, because the encapsulant has poor thermal conductivity and the heat sinks are enclosed by the encapsulant, the heat dissipation efficiency of the BGA packages is limited.
U.S. Pat. No. 6,458,626 discloses a semiconductor package having a heat sink module plate exposed externally for increasing the heat dissipation efficiency of the package. The semiconductor package is fabricated by completely enclosing an interface layer/heat sink module plate combination and semiconductor chips in encapsulant and cutting the encapsulated body. After cutting, the encapsulant above the heat sink module plate is removed by separating the interface layer from the heat sink module plate such that the heat sink module plate can be exposed externally. However, the method of the patent is complex. In addition, during the process of cutting the encapsulated body, cutting tools will cut the heat sink module plate, which is made of metal, resulting in the wear of the cutting tools. Further, the metal heat sink module plate cannot be cut neatly and smoothly, causing poor production quality. Moreover, during the encapsulation process, the encapsulant completely encloses the interface layer/heat sink module plate combination. The interface layer may be tightly adhered to the heat sink module plate by the pressure in the encapsulation process, resulting in difficult removal of the interface layer and the above encapsulant.
In view of the drawbacks of the heat dissipating designs of present semiconductor packages, a new heat dissipating design is needed.